A phase locked loop (PLL) may include a phase detector, loop filter, VCO, reference input, and frequency divider. After an initial power-on, the PLL may perform a lock acquisition process in to attempt to phase and/or frequency lock a VCO output to the reference input. Lock acquisition may take time due to an indeterminate state of the PLL at power-on.
A PLL may be calibrated or characterized to determine or generate a frequency versus tuning voltage curve for the VCO, which may be used to optimize PLL operation. Characterization may include comparing a range of voltages applied to the bias generator, to corresponding output frequencies of the VCO.
In the drawings, the leftmost digit(s) of a reference number identifies the drawing in which the reference number first appears.